Please note that Mommsen uses the AUC chronology (Ab Urbe Condita), i.e. from the founding of the City of Rome. You can use this reference table to have the B.C. dates
From: The History of Rome, by Theodor Mommsen
Translated with the sanction of the author by William Purdie Dickson
Contemporary history, again, was treated in a connected and detailed manner. Naevius described the first, and Fabius the second war with Carthage from their own knowledge; Ennius devoted at least thirteen out of the eighteen books of his Annals to the epoch from Pyrrhus down to the Istrian war;(62) Cato narrated in the fourth and fifth books of his historical work the wars from the first Punic war down to that with Perseus, and in the two last books, which probably were planned on a different and ampler scale, he related the events of the last twenty years of his life.
62. Cf. III. VII. Measures Adopted to Check the Immigration of the Transalpine Gauls
For the Pyrrhic war Ennius may have employed Timaeus or other Greek authorities; but on the whole the accounts given were based, partly on personal observation or communications of eye-witnesses, partly on each other.
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Reference address : https://www.ellopos.net/elpenor/rome/3-14-literature-art.asp?pg=94